We present the discovery of a planet on a very wide orbit in the microlensing event OGLE-2012-BLG-0838. The signal of the planet is well separated from the main peak of the event and the planet-star ...projected separation is found to be twice the Einstein ring radius, which corresponds to a projected separation of 4 au. Similar planets around low-mass stars are very hard to find using any technique other than microlensing. We discuss microlensing model fitting in detail and discuss the prospects for measuring the mass and distance of the lens system directly.
Context.
Direct imaging of Earth-like planets is one of the main science cases for the next generation of extremely large telescopes. This is very challenging due to the star-planet contrast that has ...to be overcome. Most current high-contrast imaging instruments are limited in sensitivity at small angular separations due to non-common path aberrations (NCPA). The NCPA leak through the corona-graph and create bright speckles that limit the on-sky contrast and therefore also the post-processed contrast.
Aims.
We aim to remove the NCPA by active focal plane wavefront control using a data-driven approach.
Methods.
We developed a new approach to dark hole creation and maintenance that does not require an instrument model. This new approach is called implicit Electric Field Conjugation (iEFC) and it can be empirically calibrated. This makes it robust for complex instruments where optical models might be difficult to realize. Numerical simulations have been used to explore the performance of iEFC for different coronagraphs. The method was validated on the internal source of the Magellan Adaptive Optics extreme (MagAO-X) instrument to demonstrate iEFC’s performance on a real instrument.
Results.
Numerical experiments demonstrate that iEFC can achieve deep contrast below 10
−9
with several coronagraphs. The method is easily extended to broadband measurements and the simulations show that a bandwidth up to 40% can be handled without problems. Lab experiments with MagAO-X showed a contrast gain of a factor 10 in a broadband light and a factor 20–200 in narrowband light. A contrast of 5 × 10
−8
was achieved with the Phase Apodized Pupil Lyot Coronagraph at 7.5
λ
/
D.
Conclusions.
The new iEFC method has been demonstrated to work in numerical and lab experiments. It is a method that can be empirically calibrated and it can achieve deep contrast. This makes it a valuable approach for complex ground-based high-contrast imaging systems.
Abstract
The young (50–400 Myr) A3V star
β
Leo is a primary target to study the formation history and evolution of extrasolar planetary systems as one of the few stars with known hot (∼1600 K), warm ...(∼600 K), and cold (∼120 K) dust belt components. In this paper, we present deep mid-infrared measurements of the warm dust brightness obtained with the Large Binocular Telescope Interferometer (LBTI) as part of its exozodiacal dust survey (HOSTS). The measured excess is 0.47% ± 0.050% within the central 1.5 au, rising to 0.81% ± 0.026% within 4.5 au, outside the habitable zone of
β
Leo. This dust level is 50 ± 10 times greater than in the solar system’s zodiacal cloud. Poynting–Robertson drag on the cold dust detected by Spitzer, and Herschel underpredicts the dust present in the habitable zone of
β
Leo, suggesting an additional delivery mechanism (e.g., comets) or an additional belt at ∼5.5 au. A model of these dust components is provided that implies the absence of planets more than a few Saturn masses between ∼5 au and the outer belt at ∼40 au. We also observationally constrain giant planets with the LBTI imaging channel at 3.8
μ
m wavelength. Assuming an age of 50 Myr, any planet in the system between approximately 5–50 au must be less than a few Jupiter masses, consistent with our dust model. Taken together, these observations showcase the deep contrasts and detection capabilities attainable by the LBTI for both warm exozodiacal dust and giant exoplanets in or near the habitable zone of nearby stars.
The new 8.4 m LBT adaptive secondary AO system, with its novel pyramid wavefront sensor, was used to produce very high Strehl (> ~75% at 2.16 mu m) near-infrared narrowband (Br gamma : 2.16 mu m and ...FeII: 1.64 mu m) images of 47 young (~1 Myr) Orion Trapezium theta super(1) Ori cluster members. The inner ~41 x 53" of the cluster was imaged at spatial resolutions of ~0".050 (at 1.64 mu m). A combination of high spatial resolution and high S/N yielded relative binary positions to ~0.5 mas accuracies. Including previous speckle data, we analyze a 15 year baseline of high-resolution observations of this cluster. We are now sensitive to relative proper motions of just ~0.3 mas yr super(-1) (0.6 km s super(-1) at 450 pc); this is a ~7 x improvement in orbital velocity accuracy compared to previous efforts. We now detect clear orbital motions in the theta super(1) Ori B sub(2)B sub(3) system of 4.9 + or - 0.3 km s super(-1) and 7.2 + or - 0.8 km s super(-1) in the theta super(1) Ori A sub(1)A sub(2) system (with correlations of P.A. versus time at >99% confidence). All five members of the theta super(1) Ori B system appear likely a gravitationally bound "mini-cluster." The very lowest mass member of the theta super(1) Ori B system (B sub(4); mass ~0.2 M sub(middot in circle)) has, for the first time, a clearly detected motion (at 4.3 + or - 2.0 km s super(-1); correlation = 99.7%) w.r.t. B sub(1). However, B sub(4) is most likely in a long-term unstable (non-hierarchical) orbit and may "soon" be ejected from this "mini-cluster." This "ejection" process could play a major role in the formation of low-mass stars and brown dwarfs.
This study presents the development of a basic psychological performance demand model (PDM) for sport and organisations, adopting a process view of performance underpinned by reversal theory (Apter ...2001 An introduction to reversal theory. In M. J. Apter (Ed.), Motivational styles in everyday life: A guide to reversal theory (pp. 3-36). Washington, DC: American Psychological Association). Six elite coaches with extensive coaching experience at European, Commonwealth, Olympic and Paralympic Games were interviewed. Their interview statements were analysed using a combination of deductive and inductive analysis procedures for qualitative data. In conjunction with the interviewer, coaches developed PDMs for their specific sports. Analysis of interview data and coaches' specific PDMs identified four main cross-sport themes or fundamental psychological capabilities required for meeting performance demands. These were: Mastery motivation, Decision making, Execution, and Teamship. The PDM offers a starting framework for a new basic performance model that is novel and pragmatic with potential applicability across sports and organisations. The model is useful in its existing form, but needs further testing, extended practical application and reflection by coaches, athletes, and sport psychologists. It has potential for use in other coaching contexts beyond sport, such as business, leadership development, education, and health.
We have performed H and K sub(s) band observations of the planetary system around HR 8799 using the new AO system at the Large Binocular Telescope and the PISCES Camera. The excellent instrument ...performance (Strehl ratios up to 80% in H band) enabled the detection of the innermost planet, HR 8799e, at H band for the first time. The H and K sub(s) magnitudes of HR 8799e are similar to those of planets c and d, with planet e being slightly brighter. Therefore, HR 8799e is likely slightly more massive than c and d. We also explored possible orbital configurations and their orbital stability. We confirm that the orbits of planets b, c and e are consistent with being circular and coplanar; planet d should have either an orbital eccentricity of about 0.1 or be non-coplanar with respect to b and c. Planet e can not be in circular and coplanar orbit in a 4:2:1 mean motion resonances with c and d, while coplanar and circular orbits are allowed for a 5:2 resonance. The analysis of dynamical stability shows that the system is highly unstable or chaotic when planetary masses of about 5 M sub(J) for b and 7 M sub(J) for the other planets are adopted. Significant regions of dynamical stability for timescales of tens of Myr are found when adopting planetary masses of about 3.5, 5, 5, and 5 M sub(J) for HR 8799b, c, d, and e respectively. These masses are below the current estimates based on the stellar age (30 Myr) and theoretical models of substellar objects.
We utilize the new Magellan adaptive optics system (MagAO) to image the binary proplyd LV 1 in the Orion Trapezium at H alpha . This is among the first AO results in visible wavelengths. The H alpha ...image clearly shows the ionization fronts, the interproplyd shell, and the cometary tails. Our astrometric measurements find no significant relative motion between components over ~18 yr, implying that LV 1 is a low-mass system. We also analyze Large Binocular Telescope AO observations, and find a point source which may be the embedded protostar's photosphere in the continuum. Converting the H magnitudes to mass, we show that the LV 1 binary may consist of one very-low-mass star with a likely brown dwarf secondary, or even plausibly a double brown dwarf. Finally, the magnetopause of the minor proplyd is estimated to have a radius of 110 AU, consistent with the location of the bow shock seen in H alpha .
: To report a case of polymicrobial keratitis caused by Streptococcus salivarius, Streptococcus oralis, and coagulase-negative Staphylococcus sp. in a patient who underwent collagen cross-linking for ...keratoconus.
: Case report.
: A 32-year-old male presented with a 1-day history of a painful red eye, occurring 3 days after he had undergone a collagen cross-linking with riboflavin and UV-A on his left eye for keratoconus. He admitted to removing his bandage contact lens and cleaning it in his mouth before reapplying it in his eye. On presentation, a severe keratitis with an 8-mm epithelial defect and 360-degree ring infiltrate was found. Culture results from his contact lens were positive for S. salivarius and S. oralis, and coagulase-negative Staphylococcus sp. were grown from his corneal scrapings.
: Collagen cross-linking is a promising procedure for the treatment of progressive keratoconus with minimal reported side effects. However, the possibility of a secondary infection after the procedure exists because the patient is subjected to epithelial debridement and the application of a soft contact lens. The role of the UV light on the immune mechanisms of the cornea and its effect on corneal wound healing warrant further investigation.
To report successful stromal lenticule extraction, 18 weeks after an aborted small incision lenticule extraction (SMILE) procedure.
Case report.
SMILE was planned in both eyes in another center to ...correct high myopia. The right eye was treated uneventfully with immediate lenticule extraction and normal postoperative corneal and topographic appearance. Femtosecond laser treatment was applied to the left eye, but the lenticule could not be removed and the procedure was aborted. Eighteen weeks later, lenticule extraction was attempted again with success. Uncorrected distance visual acuity improved from counting fingers to 20/15, with a successful refractive outcome as planned.
Delayed lenticule extraction was successful in achieving the target refractive outcome. To the authors' knowledge, this is the first case of successful delayed lenticule extraction following an incomplete SMILE procedure. Target refractive outcomes were achieved and there were no postoperative complications. J Refract Surg. 2017;33(3):199-202..
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